An increase in the demand of a conjugated diene including butadiene as a raw material for synthetic rubbers, or the like has been anticipated because of motorization centering on Asia in recent years. For example, a method for subjecting n-butane to a direct dehydrogenation reaction using a dehydrogenation catalyst to produce a conjugated diene (Patent Literature 1) and a method for subjecting n-butene to an oxidative dehydrogenation reaction to produce a conjugated diene (Patent Literatures 2 to 4) have been known as a method for producing a conjugated diene.